1. Field
The present invention relates generally to cryptographic systems and, more specifically, to hardware implementations of ciphers.
2. Description
Digital content is widely distributed to and among various electronic systems such as computers, networks, and consumer electronics devices, for example. The content may be audio data, video data, still image data, software, text, or any other information that may be stored in a digital form and conveyed to a user. Once the content is in a digital form, it may be easily copied or captured when the content is stored within a component of a system or is transmitted from one component to another. Developers and owners of digital content struggle to protect their intellectual property rights in the content in the face of rapid technological changes relating to such equipment. One approach to protecting the digital content is through the use of cryptography. Cryptographic systems may be used to encrypt the digital content so that only an authorized user may decrypt the encrypted data.
Various cryptographic systems are used to protect digital content. One system is the Five Company (5C) Digital Transmission Content Protection (DTCP) scheme. The DTCP approach provides manufacturers of electronic equipment with a simple and inexpensive cryptographic implementation, while maintaining a high degree of security. The DTCP approach defines a cryptographic protocol for protecting audio/video entertainment content from illegal copying, intercepting and tampering as the content traverses high performance digital buses, such as buses conforming to the Institute of Electrical and Electronics Engineers (IEEE) 1394-1995 Standard for a High-Speed Performance Serial Bus (IEEE 1394). Only legitimate entertainment content delivered to an electronics device via the same or another approved copy protection system will be protected by this copy protection system. A number of emerging technologies are taking advantage of the IEEE 1394 high speed digital interface, including desktop computer systems, digital versatile disk (DVD) players, digital televisions, and digital set top box receivers. The transparent DTCP framework used in such devices allows consumers to enjoy high quality digital pictures and sound without any noticeable performance or quality impact due to the content protection scheme.
For the DTCP approach to be widely accepted, low cost encryption and decryption components which can implement content protection without unduly delaying transmission of the digital content or causing inconvenience to the user are needed. No such components currently exist. The present invention is intended to overcome this deficiency and other disadvantages of the prior art.